1. Field of the Invention
This invention generally relates to surgical access systems and, in particular, to a surgical access port having an integral penetrating distal tip and method of using same.
2. Discussion of the Prior Art
Laparoscopic surgery typically requires an access device such as a trocar. The term trocar generally refers to a combination of cooperating elements such as a cannula, a seal housing and an obturator. The cannula defines a pathway through a body wall; the seal housing provides an isolation of that pathway; and the obturator cuts or pierces the body wall so that the cannula may be inserted. All three components are usually fitted together and used as a single unit for passage through the body wall and into a body cavity. Once the body cavity, or potential body cavity is reached with the trocar, the obturator is removed and the cannula and seal housing are used as a passageway into the body cavity.
Laparoscopic surgery can be initiated as follows: first, a large bore needle is passed through a body wall and into the internal region associated with the body wall. Next, an inflation or insufflation gas is pumped into the internal region until it is properly distended. The body wall and internal region are now ready for insertion of trocars.
A common method for inserting a trocar system through a body wall is as follows: first, a small skin incision about the length of the diameter of the cannula is made. Second, the obturator and cannula are pushed into the skin incision and are continually pushed until the system has passed through the body wall and into the interior region associated with the body wall. Third, the obturator is removed from the trocar system. The cannula and seal housing are now ready for use.
Placing a sharp instrument such as an inflation needle or trocar obturator through a body wall and into an associated internal region comes with considerable risk. The human abdomen, for example, is a tightly packed region that is filled with delicate structures and organs. There is no open space between the abdominal wall and those structures or organs until inflation gas is inserted and a pneumoperitoneum is established. Great care must be taken when placing inflation needles so as to avoid penetration of intestine, bowel or other structures. Most inflation/insufflation needles have a safety mechanism associated with the sharp end of the needle. Generally it is a spring loaded, blunted core that extends after the tip of the needle has passed through the body wall. There remains, however, a constant risk associated with the spring mechanism since the sharp needle tip extends beyond the safety core during the entire insertion process and somewhat beyond.
Even after pneumoperitoneum is established, there is a risk of injury during placement of additional sharp instruments through the distended body wall. The body wall is comprised of skin, muscle, fat and a thin membrane. The wall may be thick, muscular and tough or it may be lean and soft. As such, placement of a sharp obturator through the body wall requires great skill and knowledge of what lies within the internal region. The force required to insert a sharp trocar through a body wall can exceed forty pounds in some cases. This applied force easily overcomes the pneumoperitoneum and forces the body wall down and against delicate structures where there is the danger of piercing or cutting those structures.
This is not a new problem. Over the years there have been many solutions proposed. The shielded obturators have spring loaded or spring driven safety components that either cover the sharp portions of the obturator or retract the sharp components within the obturator shaft. These mechanisms are complex, costly and not without risk. Many surgeons have also used a technique referred to as a “cut down” procedure where successive small incisions are made until the body wall is cut through, at which time a cannula is inserted. Many feel that this procedure is safe but it is time-consuming and still has some associated risk since it continues to make use of a sharp instrument during the entire passage through the body wall. A sequential dilating system is another device that some surgeons use. This system comprises a sharp needle and associated composite sleeve that are placed into the abdomen followed by a blunted obturator. This system continues to require insertion of a sharp needle followed by the forceful placement of an obturator.
In all of the above prior art systems, the laparoscopic procedures begin with the insertion of a sharp instrument at a nearly perpendicular angle to the body wall and followed by placement of the trocars with a forceful passage of either a sharp or blunted obturator through the body wall. As explained above, a drawback of these systems is that the danger of piercing or cutting internal structures still remains.
Accordingly, there is a need in the art for a system that minimizes the risk associated with insertion of the trocar cannula while allowing the use of the most efficient penetrating profile.